Self recording dilatometer



April 25, 1933. s. SATO 1,905,607

SELF RECORDING DILATOMETER Filed Feb. 25, 1932 2 Sheets-Sheet 1 IN V EN TOR;

M/JOL BYWWW ATTORNEYS A rilzs, 1933. s. SATO 1,905,607

SELF RECORDING DILATOMETER Filed Feb. 25, 1952 2 Sheets-Sheet 2 IN V EN TOR.

Jami

A TTORNEYS.

Patented Apr. 25, 19 33 UNITED STATES.

SEIKICHI SATQQF SENDAI, JAPAN SELF RECORDING DILATOMETER Application-filed February 25, 1932. Serial No. 595,170."

My invention relates to an automatic recording device of the thermal dilatation ofa test specimen.

The object of my invention is to provlde an automatic device for mechanically recording a temperature versus thermal expansion curve or the relation between temperature and time directly without troubles and a long time even in the case of quenching a specimen wherein quick cooling is necessary so as not to be observed by an ordinary dilatometer so that the quenching effects in different cooling media and at differenttemperatures may be easily compared and the nature of quenchmg'medium and quenching methods for various ma-' terials can be simply determined, and it has useful applications in practical engineering;

Referring to the accompanying drawings,

Fig. 1 is a plan view of the present'devi'ce;

Fig. 2 is a side View of the supporting rod together with its securing parts; Fig. 3 is a sectional view taken on the line A-A of Fig.

1; Fig. f is a partial plan view of a modified form of this invention; Fig. 5 is a side view'of a constant motion transmitting device, a portion being taken in section plan view.

In orderto investigate atransformation' of iron, steel and other metals or metallic alloys during'the heat treatment, or more gen erallythe change of physical and metallurgi cal properties of such a material due to the change of temperature 'it has heretofore been considered that the most effective method is 5 to observe the change in length or volume of the material to be tested at different temperatures and there have been generally taken such steps by using a thermal dilatometer, yet in case ofa very rapid change of temperature such as in quenching process no observation can be taken by an ordinary' devi'ce.

' In such cases the temperature and thermal expansion curve may be taken on photographic plates or films bymeans of an optical device. But such a process requires much time and labour as the operation is very troublesome and also as it requires other auxiliary devices to be combined there with and it is found not only difiicult -to a common engineer who has usually no 'sufiiand Fig.6 is its cient installations of investigation, but also I i the curve obtained by. a photographing de-z woe is generallyinaccurateandnot clear. Moreover when the test piece is to-bequench-v ed in water or: oil, or other various coolants and also when the quenching'is effected inthe same .medium of different temperatures, the above mentioned ordinary process can hardly be adopted for practicaland impor tant fields. I I

My inventionis to avoid such: disadvantages. Now I will explain my invention referring to the drawings which illustrates an automatic recording device of thermal eX- pansionembodying my invention. In Fig. 5 1, 1 represents a base plate, 2 represents a bracket secured to the base 1, and from the bracket 2 is projected. a hollow supporting. rod 3 made of high refractory material having a very small coefficient of thermal expansion such as fused quartzA represents asup porting guide rod made of: high refractory metal such as nickel-chromium alloy having a guide member 5 fixed thereto. 6 and 7 are thin pipesmade of the same material as that adjusting screw 13 and to theother lever 9 is 1 attached the similar adjusting screw. '14:.

These screws are provided for adjustably supporting each end of the transmission rods 6' and 7'respectively. 17 18, 19' and 20 are joint levers forming a pantograph mecha nism, of which the lever 17 is] connected to the joint of links 10 and 11, and the lever 19 is pivoted at 23 to the base. .21 and 22 represent-balance weights. The lever 20 is extented to a required. length and has a p i Free ends of these levers 8 and 24 at its free end. 25 represents a recording board secured to the base 1 by means of'a clamping screw 29. The pivots 12 and 23 are preferably provided with ball bearings for reducing the friction. Light tension springs 15, 16 and 26 secure a good contact between'fixedand moving parts. The base 1 is provided with a handle 27 so as to facilitate the total device to be grasped by a hand and 28 represents a finger grip.

In the above device, a test piece T isto be held in position between the T-shaped end of the supporting rod 3 and the front end ofthe transmission rod 7 and a standard rod S may be put between the T-shaped end of the supporting rod 5 and the front end of'the other transmission rod 6. The standard rodSmay be made of nickel-chromium alloy or ironnickelrchromium alloy which has uniform coefiicient of thermal expansionand presents no abnormal change of the thermal expansion and has the specific heat anddensity similar to those of: the test piece T. i

low I will describe the manner of taking the temperature versus thermal expansion curve of a certain test specimen by means of the above described device embodying my invention. It is preferable to adjust counter weights 21 and 22 and also springs 15, 16 and 2621s well as adjusting screws 13 and 1a to make thelevers 8, 9, 10 and 11 to form a regular quadrilateral and to bring the pen 24 to a predetermined position on the recording board 25. After such adjustment, all partsof the present device are settled and the position of the pen is not changed even if the device is tilted or overturned. The center of the joint E between levers 10 and ll'should v preferably lie on a straight line connecting thepivot 23 andthe pen tip 24, then the curve or figure drawn on the recording board 25- by the pen 24 is similar to, but at adesired enlargement determined by the ratio of the arm length, the movementtraced by'the point- E. r The levers 8,9, and the pantographlevers are preferably made of'duralumin, as for instance, in order to possibly reduce the Weight.

I \Vhenthe scribed with the testpiece T and the stand ard rod S held in position on the T-shaped supporting rod 3, they are heated in a suitable heating furnace or other heating means. Then the thermal dilatation i.- e. (expansion or contraction) caused by the test piece and standard rod S are transmitted through the transmission rods 6 and 7-, and the movements of these rods are magnified by the levers 8 and 9, and composed by links 10,- 11 to the point E at right angles-to each other and this combined movement of the point E is still enlarged by thepantograph mechanism and drawn on the recording board 25 by the pen 24. -..The change in length ofthe stand-.

device is prepared'as above deof the test specimen at any moment, and therefore the relation between the temperature and the thermal expansion of the test rod T can be drawn on the recording board based on rectangular coordinates. The scale of temperature recorded by the thermal expansion of the rod S should be determined by a thermo-couple heated to the same condition as that of the rods S and T. It naturally depends upon tllG'COBillCiBIlt of thermal expansion of the material constituting the standard rodv S, but it can be easily predetermined.

In heating therod sand the test piece T as'they are held in position on the present device they may be placed into a furnace having a uniform distribution of temperature,

then the pen tip 24 will draw a heating curve so that the operator may inspect directly the manner of transformationoccurring 1n the test specimen. If it is desired to quench the test specimen from a desired temperature the present device may bepulled out of the furnace by the operatorjwho holds the device by thehandle 27 and the grip 28, or the presentdevice may besuspended from a suitable. support and the furnace maybe shifted along fixed rails and :thetest specimen T and the rodScan be tra'nsfered on a quenchingtub by holding the handle .27 and grip 28, and the heated portions are plunged into the quenchingfluid in the tub quickly. Then the manner and temperature of the transformation occur-ing during the course of quenching canbe directly observed by the quenching curve drawn by thepen tip 24k so tha the'quenching eifectmay be judged at once and also. theieffectj of cooling fluid on quenchingcan be judged at the same time.

,In a modified form of this invention partially shown in .Fig. 2 the lever.8 is replaced by a constant speed device 30 such as a Watch mechanism which is secured to thebase l at 4:0;- -The device530 is more clearly shown in Figs. 3- and 4, wherein-30 represents a suitable Watch mechanism or a synchronous motor (its inner gears not shown) The revolvingshaft 31 hasfixed thereto a pinion 32 by.

means of a set screw 33 and a toothed Wheel 3.4:; gearing-with the pinion 32 is securedto the end of a screw shaft 35, with which engages aJplunger 37 guided in the sleeve 36 and to the plunger 37 is conected the rodltl 39 repr'ese nts a lug for securing the constantv speed-mechanismtO the base; In some cases 65 ard rod 3 serves to indicatethe-temperature ai similar constant motion mechanism maybe secured to the end of the lever 8 in Fig. 1, or the movement of the lever 8 may be arrested by putting a piece of silica tube in place of the rod S and an uniformly revolving recording drum may be used instead of the recording board 25 to attain the object of this invention equally.

With the modified arrangement shown in Fig. 2, the time and temperature curve can be drawn by the present device. If in this case the watch mechanism 30 is not started just before the quenching is to be effected and the test piece only is heated then the pen 24 is shifted almost parallel to the axis of the test piece so that it describes the expansion only. lVhen a suitable temperature is arrived at the watch mechanism is started and the test piece is quenched into a cooling liquid, then the time and thermal expansion or contraction curve can be obtained so that the period at which the tranformation occurs during the course of quenching and also its progress can be observed. If a standard rod- S is put instead of the test piece T in the.

apparatus shown in Fig. 2 the time and temperature curve can be obtained so that it can be utilized for the comparison of cooling.

characteristics of different quenching liquids or for the observation of their cooling speeds. It will be easily understood that the device shown in Fig. 1 can be easily changed into the device partially shown in Fig. 2 by simply taking off the lever 8 of Fig. 1 and by replacing it with the watch mechanism 30 shown in Figs. 2, 3 and 4, or more simply by arresting the movement of one of the levers 8 or 9 by replacing one of the rods S or T with a piece of silica tube, thus limiting the motion of'the pen in one direction only along the axis of an uniformly revolving recording drum in place of the board 25.

In accordance with my invention the temperature and thermal expansion curve as well as the relation between the time and temperature or thermal expansion of a test piece can be directly and automatically drawn on a recording board or on the paper attached thereto by mechanical means so that it has not only the advantages of facilitating to inspect the manner of transformation occuring in the test piece but also of determining the nature of any quenching medium. The present device is of light construction and manufactured at a lower cost and adapted for easy handling.

In the foregoing description, the term thermal expansion means thermal expansion or contraction.

hat I claim as new and desire to secure by Letters Patent of the United States, is:

1. A portable self-recording dilatometer adapted for recording the relation between the temperature and the thermal change as well as their time function by entirely mechanical means on a plane recordingboard arranged in parallel on theopposite sides of said supporting rod, brackets secured to the base for slidably receiving the pipes, a pair of swing levers pivoted to said base on the same axis, one of said levers being parallel to said transmission rods while the other is arranged normally to said transmission rods in their initial positions and both levers being in engagement with said transmission rods respectively,links connected to the free ends of each of said levers to form a quadrilateral therewith, a pantograph mechanism associated with a point on said quadrilateral links, onemember of said pantograph being pivoted to said base and the last member thereof being extended to provide a pen tip, a plane recording board supported by the base to cooperate with said pen tip, springs attached to said swing levers and pantograph mechanism so as to maintaintheir nism and recorded mechanically.

2. A portable self-recording dilatometer adapted for recording the relation between the temperature and the thermal change as well as their time function by entirely me- 7 chanical means on a plane recording board in a rectangular coordinate system, as claimed in claim 1, wherein one of said swing levers is replaced by a constant speed mechanism secured to said base adapted to move its plunger along a straight line in the direction normal to the central axis of said constant speed mechanism so-as to form a quadrilateral which is connected to said pantograph mechanism.

In testimony whereof, I have signed my name this 27th day of January 1932.

SEIKICHI SATO. 

